Re: [RFC PATCH] x86/paravirt: Kill some unused patching functions

From: Juergen Gross
Date: Thu Nov 05 2015 - 06:15:22 EST

On 11/03/2015 10:18 AM, Borislav Petkov wrote:
From: Borislav Petkov <bp@xxxxxxx>

paravirt_patch_ignore() is completely unused and paravirt_patch_nop()
doesn't do a whole lot. Remove them both.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
arch/x86/include/asm/paravirt_types.h | 2 --
arch/x86/kernel/paravirt.c | 13 +------------
2 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 31247b5bff7c..e1f31dfc3b31 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -402,10 +402,8 @@ extern struct pv_lock_ops pv_lock_ops;
__visible extern const char start_##ops##_##name[], end_##ops##_##name[]; \
asm(NATIVE_LABEL("start_", ops, name) code NATIVE_LABEL("end_", ops, name))

-unsigned paravirt_patch_nop(void);
unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len);
unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len);
-unsigned paravirt_patch_ignore(unsigned len);
unsigned paravirt_patch_call(void *insnbuf,
const void *target, u16 tgt_clobbers,
unsigned long addr, u16 site_clobbers,
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index c2130aef3f9d..4f32a10979db 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -74,16 +74,6 @@ void __init default_banner(void)
/* Undefined instruction for dealing with missing ops pointers. */
static const unsigned char ud2a[] = { 0x0f, 0x0b };

-unsigned paravirt_patch_nop(void)
- return 0;
-unsigned paravirt_patch_ignore(unsigned len)
- return len;
struct branch {
unsigned char opcode;
u32 delta;
@@ -152,8 +142,7 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
/* If there's no function, patch it with a ud2a (BUG) */
ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
else if (opfunc == _paravirt_nop)
- /* If the operation is a nop, then nop the callsite */
- ret = paravirt_patch_nop();
+ ret = 0;

/* identity functions just return their single argument */
else if (opfunc == _paravirt_ident_32)

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